This invention relates to the conversion of nuclear energy to electrical energy and, more particularly, to the piezoelectric conversion of fission fragment energy to electrical energy. This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).
Nuclear fission releases substantial energy. For example, a single fission of a U.sup.235 atom will produce 3.2.times.10.sup.-11 watt-second, with the energy carried in two fission fragments and about two and a half neutrons on an average. The fission fragments are roughly equal in mass with an energy of about 100 Mev. Thus, fissioning one gram of U.sup.235 would produce 23 Mw-hours of energy, or the equivalent of about 4,000 gallons of gasoline, if fissioned completely.
Fission energy is typically converted to electrical energy by a thermal process. Nuclear reactors capture the fission fragment energy in surrounding fuel, structure, and moderator, wherein a coolant removes the heat energy for transfer through a heat exchanger to produce steam for driving a turbine and connected electrical generator. Thermionic converters directly convert the heat to electrical energy. However, nuclear reactors are necessarily large and complex devices that output megawatts of power. Thermionic devices are relatively inefficient and generate waste heat for disposal.
It would be desirable to convert nuclear fission energy directly to electrical energy. This conversion is accomplished by the present invention wherein a piezoelectric film generates an output voltage in response to fission fragment energy.
It is an object of the present invention to convert nuclear fission energy to electrical energy using a piezoelectric effect.
It is another object of the present invention to provide portable converters for directly converting energy from radioactive decay particle emissions to electrical energy.
One other object is to provide for using fissionable nuclear waste to generate electricity.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.